(1) Field of the Invention
The invention relates to an optical disk drive structure, and more particularly to the interior structure of the disk drive having an adjustable bearing mechanism for guide bars that can be used to calibrate the position of the corresponding guide bar.
(2) Description of the Prior Art
Referring to FIG. 1 and FIG. 2, a conventional disk drive with its housing removed is shown in a perspective view and a planar top view, respectively. As shown, a base 1, particularly the top surface 10 thereof, is used as a platform to mount major components of the disk drive. These major components include a spindle motor 11, an optical pickup head 12, and a pair of guide bars (a main guide bar 13 and a secondary guide bar 14) to carry the optical pickup head 12 and guide the optical pickup head 12 to move linearly back and forth with respect to the spindle motor 11.
The spindle motor 11 is used to bear and rotate a disk (not shown in the figures). The optical pickup head 12 is driven by a motor via a spiral bar or a gear set (not shown in the figures) to move linearly back and forth with respect to the spindle motor 11. Upon such an arrangement, the optical pickup head 12 can capture the data recorded on the disk sustained and rotated by the spindle motor 11. As shown, the optical pickup head 12 rides over the main guide bar 13 and the secondary guide bar 14, in which each end of either the main guide bar 13 or the secondary guide bar 14 is mounted on the top surface 10 of the base 1 by a bearing structure 15.
In the art, as long as the bearing structure 15 is fixed to the base 1, no further adjustment can then be applied to move even slightly its position on the top surface 10. It implies that the spacing between the main guide bar 13 and the secondary guide bar 14 is firmly fixed after all four bearing structures 15 are anchored in position.
Generally, while the optical pickup head 12 reads the disk on the spindle motor 11, most of reading errors are caused by the misalignment between the spindle motor 11 and the optical pickup head 12. As shown in FIG. 2, the foregoing misalignment can be evaluated by judging the difference between a spacing D1 and a spacing D2, in which the spacing D1 is the distance from a center of the spindle motor 11 to the main guide bar 13 and the D2 is the distance from a center of the optical pickup head 12 to the main guide bar 13. In the case that the D1 is equal to the D2, it implies that no misalignment between the spindle motor 11 and the optical pickup head 12 exists. Otherwise, an offset in alignment does definitely exist in between.
It is well known in manufacturing the disk drive that a minor offset misalignment between the spindle motor 11 and the optical pickup head 12 is inevitable. Yet, in the case that a major offset misalignment is unfortunate to exist in between, a substantial bad influence will occur to worsen the reading precision of the optical pickup head 12. Sometimes, such an influence is directly related to the frequently reading failure in a disk drive. However, to correct the aforesaid misalignment simply by adjusting any of the bearing structures 15 that hold the main guide bar 13 and the secondary guide bar 14 is usually unpractical. Generally, massive disassembly and assembly of the disk drive may be required to correct the misalignment. Sadly, even though efforts may have been applied to correct the misalignment in the disk drive, yet it does not surely mean that the misalignment problem can be successfully corrected.
Therefore, an improvement that can satisfactorily correct the aforesaid misalignment between the spindle motor 11 and the optical pickup head 12 without involving too much disassembly/assembly work is definitely welcome to the skilled person in the art.